WEST PALM BEACH, Florida — Cigarettes and their filters topped the list of trash items culled from beaches worldwide during last year's annual international coastal cleanup, according to a report.

More than 450,000 volunteers removed 8.2 million pounds (3.7 million kilograms) of debris from 18,000 miles (29,000 kilometers) of coastline and waterways in 74 countries during the daylong cleanup in September, The Ocean Conservancy said in a report scheduled for release Thursday. The group has sponsored the worldwide volunteer effort for 20 years.

"Marine debris kills wildlife and is a threat to the local environment, not to mention an eyesore," said director Vickie Matter. "The information we've gathered over the past 20 years shows that it's ultimately a manmade problem, which means it is highly solvable."

Kathryn Novak, the group's Florida coordinator, said Florida's 1,200 miles (1,900 kilometers) of coastline and dozens of endangered or threatened species makes it especially vulnerable to litter.

"Plastic bags are one of the most common items that we find and they resemble jelly fish which is one of the favorite foods of sea turtles," Novak said.

Since 1986, more than six million volunteers in the project have removed 109 million pounds (49 million kilograms) of trash from 179 million miles (288 million kilometers) of beaches and waterways in 127 countries, according to the Washington-based environmental advocacy group.

Of the 6.2 million items of debris collected worldwide last year, cigarettes and cigarette butts accounted for roughly 1.6 million. Coming in a close second at 1.3 million were caps and lids, food wrappers and containers.

The United States had the most participants, according to the report, with 174,000 people cleaning some 3.9 million pounds (1.8 million kilograms) of trash from nearly 14,000 miles (22,000 kilometers) of waterways and coastlines.

The Philippines saw the second best participation with about 123,000 people, followed by Canada where slightly more than 21,000 volunteers helped out.